Lathe



Dec. 28, 1937.

c. A. BIRKEBAK LATHE 5 Sheets-Sheet l Filed June 20, 1935 ATTORNEYfi.

Dec. 28, 1937.

C. A. BIRKEBAK LATHE Filed June 20, 1935 3 Sheets-Sneef, 2

9' ATTORNEYfi Dec. 28, 1937. c. A. BIRKEBAK LATHE Filed June 20, 1935 3 Sheets-Sheet 5 INVENTOR. ($725224)? 5 Z Z Y ATTORNEYS.

Patented pec; 28, 1937 Christian A. Birkebak, Detroit, Mich, assignor to Ex-Cell-O Corporation,- a corporation of Mich igan Application June 20, 1935, Serial No. 27,506

. I 7 Claims. r01. sa-zr The present invention relates to improvements in machine lathes.

The object of the present invention is to provide a lathe capable of machining non-circular objects.

It is also an object of the present invention to provide a lathe capable of machining, a tapered object.

It is also an object of the present invention to provide a lathe construction in which the tool carriage is given oscillatory motion in order to produce a non-circular machining action.

It is also an object of the present invention to provide a'lathe construction of the last mentioned type embodying mechanism capable of causing the tool carriage to oscillate a plurality of times during each revolution of the lathe spindle to thereby provide for a substantially non-circular machining action.

20 It is also an object of the present invention to provide a lathe construction which includes a tool carrier which may be adjusted to provide a tapered machining action.

It is also an object of the present invention to 25 provide a lathe construction in which the tool carriage is vertically supported on the front face of the lathe.

It is also an object of the present invention to provide a lathe construction of the last men 30 tioned type in which thetool carriage is support ed on a pair of eccentric shafts, and in which the tool carriage is advanced by a fixed lead screw.

- It is also an object of the present invention to J provide a lathe construction of the last mentioned type and embodying means to rotate at least one of the eccentric shafts in order to produce a non-circular machining action.

It is also an object of the present invention to 40 provide a lathe construction embodying eccentric shafts to support a tool shaft and embodying to provide a lathe construction of the last men- .the line |0l0 of Fig. 9;

tioned type by which the adjusting means comprises an active and a dummy screw which may be alternatively positioned and the alternative positions of which readily indicate the adjustment.

It is also an object of the present invention to generally improve thecons truction of machine lathes and to provide a machine lathe which is economical of manufacture and which is positive and accurate in operation. 10 Other objects and advantages of the present invention appear in the following description and the appended claims.

In the drawings, throughout which corresponding reference characters designate corresponding partsz' Fig. 1 is a view inside elevation of an illustrative embodiment of the present invention; Fig. 2 is a top plan view, with certain of the parts broken away, of the embodiment shown in Fig. 1, but with the tool carriage placed to the right from the position shown in Fig. 1;

Fig. 3 is'a view in vertical section taken along the line 33 of Fig. 1;

Fig. 4 is a view in vertical section taken along the line 4-4 of Fig. 3;

Fig. 5 is a view in vertical section taken along the line 5-5 of Fig. 3;

Fig. 6 is a view in vertical section taken along the line 6-6 of Fig. l; Fig. 7 is a view invertical section taken along the line l-lvof Fig. 1;

Fig. 8 is a view in vertical section taken along the line 88 of- Fig. 2;

Fig. 9 is a view in end elevation of the embodiment shown in Figs. land 2;

Fig. 10 is a view in vertical section taken along Fig. 11 is a view in vertical section taken along the line ll-ll of Fig. 10; Fig. 12 is a view in vertical section taken along the line l2--l2 of Fig. 1;

Fig. 13 is an illustrative elevational view illustrating the tapered construction produceable in the practice of the present invention; and 5- Fig. 14 is a view in vertical section taken along the line I4-l4 of Fig. 13, and illustrating the elliptical construction produceable in the practice of the present invention.

In' the form illustrated, the present invention comprises generally a supporting bed plate, head and tail stock between which the piece or stock to be worked up is supported for rotation by the head stock, and a tool carriage movable along the bed plate. Any conventional mechanism Prei'erably, and as illustrated, the tool carriage lead screw is suitably geared to the work spindle driving mechanism so that a single source of a power ls sufficient for the lathe.

The tool carriage, which may embody conventional means to support and present a tool to the stock, is movably supported on the bed plate,

and is connected to a lead screw for movement along the face of the bed plate. The support for the tool carriage is also arranged so that, in machining non-circular surfaces, the tool carriage may be oscillated inwardly and 1 outwardly with respect to the'work, in timed fixed relation to the rotation 01' the work. The arrangement is also such that in machining tapered work shaft suitably secured to the bed plate.

the tool carriage support may be adjusted so that as the tool carriage advances along the bed plate the toolcarriage is progressively moved inwardly or outwardlywith respect to the work.

As illustrated, the support-for 611850011081- riage comprises an upper and a lower eccentric oscillatory movement of the tool carriage is produced by oscillating the upper eccentric shaft in timed relation to the rotation of the work and work spindle. As. illustrated, the construction is arranged to produce elliptical machining and, accordingly, the connections between the upper eccentric and the driving or work spindle are such that the eccentric makes two oscillations for each revolution of the spindle. In the course of the oscillatory movement, the tool carriage oscillates about the lower eccentric shaft asanaxis.

In accordance with the present invention, and

7 as illustrated, the-connections between the tool carriage and the lead screw are able to take up the movement of the tool carriage so that I the lead screw may be fixed in position with respect to the bedplate. This arrangement, as

which are interchangeable.

, the bed plate, the tool carriage follows a path; er at an angle to or parallel to the axis of will appear more fully hereinafter, substantially simplifies the construction of the lead screw and associated parts. The upper eccentric shaft is readily connectible to and disconnectible from the oscillatory mechanism, so'that the change from circular to non-circularmachining action is. readily accoinplished. The adjusting means comprises an'active and a dummy screw, which may be given simple identifying characters, and the positions of With the screws in one relative position, the active screw keys the upper shaft to the oscillating mechanism and when in the reverse position the upper shaft is released from such oscillating mechanism and.

held against movement. 7

A corresponding end of each of the eccentric supporting shafts is adjustable. towards and away from the bed plate, and suitable. indicating gauge mechanism is provided to indicate the positioning of these members. As will be understood, depending upon the spacing of the adjustable ends of the shaft from the bed plate, relative to the spacing of theother ends thereof. from The- V 7 9,108,815 may be utilized to rotate the work spindle.

be conveniently accomplished by slightlyrotating the lower eccentric shaft with respect to the upper so as to vary the axial spacing of the shafts. 1

Considering the above discussed elements in more detail, and referring to Figs. 1, 2 and 9, illustrative stock 28 is supported between head stock 22 andtail stock 24. Head stock 22 is fixed in position on table 26, in any conventional man'- ner, and is provided with an opening, normally closed by plate 28, to afford access to the interior thereof. Tail stock 24 is preferably slidably supported ontable 28, and arranged to be locked in position at any suitable point therealong, in any conventional'ma'nner. Dead cen-' ter 28 is preferably adjustable'longitudinally of tailstock 24, by adjusting screw 38, and may be locked in any desired position by locking screw 32.

The driving spindle for stock 28 comprises the tubular sleeve 34, which is journaled in head stock 22 within suitable ball bearing assemblies 38 and 31, and the enlarged end of which extends through the end of head stock 22 to form the 4 face plate 38. Rollerbearing unit 31 is seated between the shoulder 48 formed on sleeve 34, and

the bushing 42, which is retained in place thereon by lock nut 44. Ball bearing unit 88 is suitrounds sleeve 34. Sleeve 48 also abuts against one hub 58 of gear 52, and'retains the opposite hub 5| of the latter in engagement with the ably keyed, by key 46, to sleeve 48, which sur shoulder 54, formed on sleeve 84. Gear 62 is keyed to sleeve 34 by key 53 (Fig. 12k Sleeve 34 8 extends beyond the outer end of stock 22 and the driving pulleys 54 are secured thereto by set screw 55. As will be understood, pulleys 54 may be connected to any suitable source of power.

The shank 68 of adjusting wheel 82 extends through sleeve 34 and is externally threaded at its innerend 63, to cooperatewith the internal threads 64 provided in the shank 88 of boss 88. The shank 66 of boss 68 is slidable in the recess 18 formed in sleeve 84, but relative rotation between spindle 68 and sleeve 34 is prevented by key 12. i

As will be understood, the end formation of boss 68 is determined by the character of the stock to which it is to be connected. The illustrated stock 28 is the piston of an internal combustion engine, and accordingly as best shown in Fig. 8, the end of boss 88 is shaped to fit somewhat snugly bet'ween the bearing bosses 14 which conventionally extend inwardly from the side walls of piston 28.

Rotation of hand wheel 82 in one direction draws boss 88 inwardly within sleeve 34, finally bringing the shoulder 16 into solid engagement with the collar 18, and forcing the latter into engagement with face plate 38. A rigid driving assembly is thus provided. Thereafter stock 28 may be placed over the end of vboss 68, as illus- The upper and lower shafts 82 and 84 each in-.-

clude a circular central section 88,.and 88, re-

spectively, and end sections'of reduced diameter.

I00 and I02, and I04 and I06, respectively, which are eccentrically formed with respect tothe central sections,- and are supported on table 26 in the manner described later. The central section 96 of shaft 92 is slidably received in a correspondingly shaped section of carriage 90, as

best shown in Fig. 7. The central section 98 of shaft 94 passes through two bearing sections I08 and H0 formed at the lower corners of carriage 90.

Theunderside of shaft 92 is formed with rack teeth II2 for cooperation with a spur gear II4 (Fig. 7). Spur gear H4 is secured on a shaft II6, to which a hand wheel H8 is suitably secured, and which is retained in position with respect to carriage 90 by set screw I20. The connection between spur gear I I4 and rack teeth II2 includes some free spacing of the teeth, permitting a limited amount of rotation of shaft 92 with respect to carriage 90 for a purpose described later. As will be understood, rotation of hand wheel H8 in one direction or the other advances carriage 90 along table 26 in a corresponding direction, providing a manual adjustment of the position thereof.

The cutting tool I22 may be supported on tool carriage 90 in any desired conventional manner. A preferred construction is illustrated in detail in Fig. 3, in which cutting tool is secured by set screw I24 in a sleeve I26. Sleeve I26 is slidably supported in the outer sleeve I28, which in turn is suitably supported in any desired manner on carriage 90, and is internally threaded to.

the adjusting screw I30. Handle I92 is provided to turn screw I30. 'As will be understood, rotation of the screw I30 moves tool I22 inwardly or outwardly with respect to stock 20. Locking screw I34 is provided to lock the tool I22 in any desired position.

Referring particularly to Figs. 1, 4 and 5, the illustrated lead mechanism for tool carriage 90 comprises the screw I40, one end of which is rotatably supported in standard I42, which is, in turn, secured to table 26 by bolts I44. The other end of screw I40 passes through the collar I46 formed in table 26, and, as shown in Fig. 12, has a worm gear I50 secured upon it in any suitable manner, as by the nut I48. The worm gear I50 meshes with the worm I52, secured on the same shaft as the worm wheel I54, and which in turn meshes with worm I56. Worm I56 is suitably secured to a shaft 151 which is suitably journalled in and passes through an intermediate wall 56 formed in table 26. A spur gear I59 secured on shaft I51 meshes with gear 52. The bearing standard I58 for gears I52 and I54 is suitably secured to wall 56 by bolts I60.

Any desired mechanism may be employed to clutch tool carriage 90 to lead screw I40, and to unclutch it therefrom. The illustratedmechanism, as best shown in Figs. 3, 4 and 5, comprises the two jaws I10 and I12 which are normally biased apart, releasing screw I40, by springs I14,

screw I40. Rotation of member I82 in a clockwise direction as viewed in Fig. 4, separates pins I16 somewhat, and results in a separation of jaws I10 and I12. An automatic release of the jaws is provided by the plunger I90, which is slidably received in a cooperating opening formed in car-- the elongated slot I96 in pin I90'and suitably secured in carriage 90. It will be understood that inward movement of pin I90 rotates member I82 in the clockwise direction as viewed in Fig. 4 and releases the jaws I 10 and I12 in the manner just described. Pin I90 is positioned to engage a stationary part of the lathe, when carriage 90 reaches or approaches the'limit of its movement. As shown in Figs. 1 and 2, stopping stud I98 is secured to table 26 for cooperation with pin I90.

Referring to Figs. 3 and 5, in order to accommodate the oscillatory motion of the tool carriage 90, later described, the connection between the carriage and the'lead screw I40 includes the intermediate member I18, which may ing jaws I12 and -I10. The connection allows a limited amount of transverse movement between jaws I10 and I12 and member I18, but restrains longitudinal movement. The play thus provided permits carriage 90 to oscillate with respect to the relatively stationary lead screw I40.

Considering now the mounting of the eccentric shafts 92 and 94 on the table 26, and-referring particularly to Figs. 1, 2 and 9, the end I06 of shaft 94 is pivotally supported in a boss I01 formed in table 26. The end I02,of shaft 92 passes through a cooperating opening 200 formed in table 26, and extends sumciently bemain spindle gear 52. The eccentric connection for rocker arm 208 is shown in detailvin Figs. 10 and 11, andcomprises the eccentric sleeve 2I2, keyed to shaft I51 by key 2I4, and journalled in the circular end of arm 208 within the roller bearing unit 2I6. tain eccentric 2I2 in place on shaft I51.

With this arrangement, it will be understood that rotation of spindle 34 and consequently of The nut 2 I8 is provided to re-- yond the table 26 to receive'the oscillating arm stock 20, is accompanied byan oscillatory motion of rocker arm 208 and arm 202, resulting in a reciprocation of shaft section -'I02. Because of the eccentricity between the central section 96 of shaft 92 and the end section I02, this reciprocation of section I02 causes the upper edge of tool carriage 90 and tool I22 to move inwardly and outwardly with respect to stock 20. It will be further understood that the number of inward and outward movements of carriage 90 and cutting tool I22 for each revolutionof stock 20 is determined by the gear ratio between the driving gears 52 and I59 (Fig. 12). The illustrated ratio is two to one, so that an elliptical shape of stock 20 is produced, as illustrated in Fig. 14, in which the portions 2I are drawn from a major axis produced by the periodic withdrawal of tool I22, from stock 29.-- It will be further understood that the relation between the major and minor axes of the elliptical shape produced may be readily adjusted by replacing eccentric bushing 2l2 with a corresponding bushing that is of greater or less eccentricity as desired. A

It will be understood that by removing the set screw 294 (Figs. 1 and 2), the arm 292 is released from the shaft section 192 so that the latter is unafiected. by movement of rocker arm 299.

Under these conditions, no oscillatory movementof tool carriage results, and the lathe is effective to produce a circular shape of stock 29. By placing set screw 294 in the opening illustrated as occupied by screw 229, rotation of shaft 92 is prevented.

In accordance with the present invention, a convenient indication of the condition of the lathe V is provided by the use of the set screw294 and the cooperating dummy set screw 229, the upper surfaces of which are preferably provided with distinguishing characteristics, such as A and 1B. When in the relative positions shown in Fig. 1, the lathe, as described, is eifective to produce an elliptically shaped stock 29. By reversing the positions of the two screws 294 and 229, the lathe is conditioned, as described, to produce a circularly shaped stock 20.

It will be noted that carriage 99 oscillates about shaft 94 as an axis, and that the radius of rotation, which is equal to the spacing between centers of shafts 92 and 94, is larger than the radius of oscillation of the axis of the central section 99.

of shaft 92, which is equal to the eccentricity of the section 99 of shaft 92. The oscillatory movements are, however, relatively minute, and it has f been found, in the practice of. the present invenu eccentric type, each of which is arranged as' vided to give a visual indication of the positions I vertical position. It will be understood that the tion, that the displacements introduced by-the shown in Fig.6. Referring to Fig. 6, which corresponds to the mounting of the end of shaft 92, the section I99 is rotatably mounted within the eccentric bushing 222, which in turn, is rotatably mounted within the bearing standard 224. Bearing standard 224 is suitably secured to, or forms a part of, table 29. Eccentric bushing 222 is connected by a set screw 229 for rotation in response to an am 229. An indicating scale 299 is proof the parts. The-mounting for the 'end section I94 of shaft 94 is correspondingly arranged and comprises, (Fig. 1), the eccentric 292, the operating arm 294 and the scale 239. It will be understood that in each adjustment, botharms 229 and 294 should be moved through thesame angle in order to maintain the carriage 90 in a adjustment thus afforded is minute and may readily be absorbed ,by the mountings described for the other ends of shafts 92 and 94,

- It will be noted that the taper adjustment mechanism is independentof the oscillatory mechanism described above, and the lathe is thus effective to'produce either circular or noncircular shapes of either uniform or tapering diameter. a a

As mentioned it has been'found to be desirable in the practice of the present invention to provide means to adjust the spacing between the shafts 92 and 94 to prevent chattering of the tool carriage and keep the machining action within close limits. As-shown in Fig. 1, this is accomplished by the member 249 and cooperating parts. Member 249 comprises a lower boss. portion which is apertured to snugly receive the central section 99 of shaft 94, and an upwardly extending arm which is apertured to loosely pass over a. stud [242 which is stationarlly secured by being threaded into table 29. Adjusting nut 249 'is threaded on stud 242 and may be turned on or off to adjust member 249. A-biasing spring 249 (Fig. 2), interposed between table 29 and the arm of member 249, surrounds stud 242, and maintains the arm in engagement with nut 249. Set screw 241 is provided to lock the boss portion to shaft section 99. {It will be evident accordingly that an adjustment of nut 243 correspondingly rotates shaft section '99. Because of the eccentricity of shaft 94, this rotation increases or decreases the spacing between centers of sections 99 and 99 of shafts 92 and 94 respectively. The

adjustments required are relatively minute, and

any movements'of member 249 transversely of stud 242 involved in the adjustments are taken up by the loose connection between member 249 and .stud 242. I

Although a specific embodiment of the present invention has been described, it will be evident that various changes may be-made in the form,

- number and arrangement of parts within the scope thereof, asdeilned in the appended claims.

What is claimed is: 1. A machine lathe comprising a table for supporting stock to be machined, a tool carriage for presenting a cutting tool to said stock, means for reciprocating said tool carriage transversely of said stock comprising a rocker arm and an eccentrically formed shaft, said rocker arm having a locking opening disposed to receive a locking screw to lock said shaft to said rocker arm, a stationary member having a second locking opening to receive a locking screw to lock said shaft against motion, and a pair of characteristically difierent locking screws for insertion in said openings, one of said screws being effective to produce a locking or oscillatory action and the other ineffective, whereby the condition of the machine lathe is indicated by the relative positioning of said first and second locking screws.

2. A machine lathe comprising in combination, a table, means for supporting stock upon said table for axial rotation, a carriage for supporting a tool in cutting relation to said stock, a first eccentric shaft, means supporting said shaft upon said table so as to extend generally parallel to the axis of said stock, means forming a pivotal connection between said tool carriage and said shaft, a second eccentric shaft, means supporting said second eccentric ,shaft'upon said table so as to extend generally parallel to the axis'of said stock, means forming a connection between said second eccentric shaft and said carriage whereby angular movement of said secfirst eccentric shaft to effect an adjustment of u Q work, and means for oscillating the eccentric shaft through a limited angle less than that of a complete rotation and in timed relation to the work rotation, whereby such oscillation enables moving the tool accurate and small amounts to and from the axis of work rotation.

4. A machine tool comprising a base, rotary.

work stock supporting means, a tool holder hav: ing a tool adapted to engage the work, means including a shaft extending substantially parallel to the work axis forpivotally mounting the tool holder on the base, an eccentric shaft extending substantially parallel to the first mentioned shaft and operatively engaging the tool holder for moving it inwardly and outwardly with respect to the work axis, means for rotating the work, means'for oscillating the eccentric shaft through a limited angle less than that of a complete rotation and in timed relation to the work rotation, whereby such oscillation enables moving the tool accurate and small amounts to and from the axis of work rotation,, and meansfor feeding the tool holder'along the shafts during such oscillatory movement.

5. A machine tool comprising a base, rotary work stock supporting means, a tool holder having a tool adapted to engage the work, means including a shaft extending substantially parallel to the work axis for pivotally mounting the tool holder on the base, an eccentric shaft extending substantially parallel to the first mentioned shaft and operatively engaging the tool holder for moving it inwardly and outwardly with respect to the work axis, means for rotating the work, means for oscillating the eccentric shaft through a limited angle less than that of a complete rotation and in timed relation to the work rotation, whereby such oscillation enables moving the tool accurate and small amounts to and from the axis of work rotation, means for feeding the tool holder along the shafts during such oscillatory movement, and adjustable means for supporting the shafts at one end to enable varying their position with respect to the work axis of rotation.

6. A machine tool comprising a base, rotary workfstock supporting means, a tool holder having a tool adapted to engage the work, means including a shaft extending substantially parallel to the work axis for pivotally mounting the tool holder on the base, an eccentric shaft extending substantiallyparallel to the first mentioned shaft and operatively engaging the tool holder for moving it inwardly and outwardly with respect to the work axis, means for rotating the work, means for oscillating the eccentric shaft through a limited angle less than that of a complete rotation and in timed relationv to the work rota tion, and means for adjustably moving one end of the shafts soas to vary the direction in which they extend along the work axis.

7. A machine tool comprising a base, means on the base for supporting work stock for rotation about an axis, a tool holder for supporting a tool in cutting relation to the stock, a shaft journalled on the base and extending generally parallel to r the axis of stock rotation and having an ecceneccentric'portion thereon so as to relatively adjust the tool holder andshafts transversely to the latter.

CHRISTIAN A. BIRKEBAK. 

